The present invention relates generally to a new family of biodegradable, environmentally friendly poly(aspartic acid) polymers and copolymers. More specifically, the present invention relates to modified poly(aspartic acid) polymers useful in water treatment applications for corrosion and scale control.
Poly(amino acids) are generally known in the art of corrosion and scale control. One commonly used poly(amino acid) is poly(aspartic acid). Poly(aspartic acid) is known to be biodegradable. The biodegradability and environmentally friendly nature of polyaspartic acid is important, particularly in the offshore oil and gas industry due to the increased international concerns over marine pollution and the increased restrictions imposed on offshore oil and gas rigs relating to chemical discharges. In the future, it is anticipated that the chemicals discharged from oil and gas rigs will be evaluated under a standardized system using the Organisation for Economic Co-operation and Development (OECD) guidelines. These guidelines are published and currently available.
While it is known that poly(aspartic acid) is biodegradable under the OECD guidelines, many modified poly(amino acids) and modified polyaspartic acids are not biodegradable. Further, while poly(aspartic acid) is somewhat effective at corrosion inhibition and scale control, poly(aspartic acid) is not a universal solution to corrosion inhibition and scale control on metallic surfaces of industrial water systems and in oil field environments. Specifically, one known product that includes imidazolium and an additive is known to be a superior corrosion inhibitor in stirred kettle tests simulating oil field conditions. However, imidazolium compounds are not biodegradable.
Accordingly, there is a need for an improved compound for reducing corrosion and inhibiting scale formation on metallic surfaces in industrial water systems and on metallic surfaces in an oil field environment. Any such compound must be environmentally friendly or deemed biodegradable under OECD guidelines.